Genetic analysis of the transcriptional arrangement of Azotobacter vinelandii alginate biosynthetic genes: Identification of two independent promoters
Por:
Lloret L., Barreto R., Léon R., Moreno S., Martínez-Salazar J., Espín G., Soberón-Chávez G.
Publicada:
1 ene 1996
Resumen:
The study of alginate biosynthesis, the exopolysac-charide produced by Azotobacter vinelandii and Pseudomonas aeruginosa, might lead to different bio-technological applications. Here we report the cloning of A. vinelandii algA, the gene coding for the bifunctional enzyme phosphomannose isomerase- guanosine diphospho-D-mannose pyrophosphorylase (PMI-GMP). This gene was selected by the complementation for xanthan gum production of Xanthomonas campestris pv. campestris xanB mutants, which lack this enzymatic activity. The complementing cosmid clones selected, besides containing algA, presented a gene coding for an alginate lyase activity (algL), and some of them also contained algD which codes for GDP-mannose dehydrogenase. We present here the characterization of the A. vinelandii chromosomal region comprising algD and its promoter region, alga and algL, showing that, as previously reported for P. aeruginosa, A. vinelandii has a cluster of the biosynthetic alginate genes. We provide evidence for the presence of an algD-independent promoter in this region which transcribes at least algL and algA, and which is regulated in a manner that differs from that of the algD promoter.
Filiaciones:
Lloret L.:
Depto. de Microbiol. Molecular, Institute de Biotechología, Univ. Nac. Auton. de México, Apartado Postal 510-3, Cuernavaca 62250 Morelos, Mexico
Barreto R.:
Depto. de Microbiol. Molecular, Institute de Biotechología, Univ. Nac. Auton. de México, Apartado Postal 510-3, Cuernavaca 62250 Morelos, Mexico
Léon R.:
Depto. de Microbiol. Molecular, Institute de Biotechología, Univ. Nac. Auton. de México, Apartado Postal 510-3, Cuernavaca 62250 Morelos, Mexico
Moreno S.:
Depto. de Microbiol. Molecular, Institute de Biotechología, Univ. Nac. Auton. de México, Apartado Postal 510-3, Cuernavaca 62250 Morelos, Mexico
Martínez-Salazar J.:
Depto. de Microbiol. Molecular, Institute de Biotechología, Univ. Nac. Auton. de México, Apartado Postal 510-3, Cuernavaca 62250 Morelos, Mexico
Espín G.:
Depto. de Microbiol. Molecular, Institute de Biotechología, Univ. Nac. Auton. de México, Apartado Postal 510-3, Cuernavaca 62250 Morelos, Mexico
Soberón-Chávez G.:
Depto. de Microbiol. Molecular, Institute de Biotechología, Univ. Nac. Auton. de México, Apartado Postal 510-3, Cuernavaca 62250 Morelos, Mexico
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